In recent years, the number of pixels in image sensors of digital cameras, video cameras, and so on has increased, which has led to an increase in resolution of images captured by the image sensors. However, such increase in the number of pixels causes reduction in the amount of light received per pixel, resulting in a problem of much noise in the captured images.
In order to suppress the noise caused by the reduced amount of light received and to capture images with a high sensitivity and a high resolution, conventional cameras have employed the technique of continuously capturing a plurality of images and synthesizing the continuously-captured images into one image.
With such continuous capturing of images and synthesizing of the continuously-captured images, images (continuously-captured images) are captured with a shutter speed at which the exposure time is relatively short, and then the continuously-captured images are aligned and synthesized, so that the resolution is maintained and the noise is reduced. Thus, although the amount of light received is reduced, it is possible to maintain the small amount of noise and the high level of resolution.
A technique of appropriately setting camera parameters in such continuous capturing of images and synthesizing of the continuously-captured images is disclosed.
An example of such parameter setting technique is, as disclosed in Patent Literature 1, to set a shutter speed which is fast enough to make it insusceptible to hand shaking, and to control, according to the luminance of the object, the sensitivity and the number of images to be captured, to thereby generate a synthesized image having a high resolution and a high sensitivity from an appropriate number of continuously-captured images.